Spark-plug.



C. 0. BLDRIDGE @L RJ. BBEBB. SPARK PLUG.

APPLICATION FILED FEB. 17, 1911.

1,01 1,595. -Pantedea 12,1911.

f f@ fra STARS oFFiCE-.f

CHARLES C. yELD:RIDGE AND EJWIN J. BEEBE, OF MARSHALLTOWN, IOWA.

SPARK-PLUG.

Specification of Letters Patent.

Patented Dec. 12, 1911.

Application filed February 17, 1911. Serial No. 609,217.

Iprovements in Spark-Plugs, of which 'the following is a specification.

The object oitI this invention is to produce an improved spark plugadapted to draw a large spark and one which will need cleaning lessfrequently than .plugs heretofore produced.

In the .accompanying drawings, Figure 1 is 'a side elevation of a sparkplug embodying the features of our invention. Fig. 2 is an end view, andFig. 3 a longitudinal central section through the plug.

The present embodiment of ourinvention comprises a casing l, in thisinstance in the form of a bushing adapted to be screwed into an enginecylinder.- Within the casing is secured an insulating member 2 andextending through said insulating member is a rod 3 forming one of theelectrodes of the spark plug. Upon the upper end of the rod 3 is mountedsuitable means 4 for attaching an electric conductor to the rod. Theother electrode 5 of the plug consists of a Wire of general U shape",the free ends of the arms ot the electrode being secured in the endV otthe casing l in any suitable way. vAs shown in the drawings, the outerportion of the electrode is shaped to lie more or less'closely alongthev end portion of the central electrode tor a considerable distance.By reason oi this shape of the lower end of the electrode 5 arelatively' large spark is formed between the two electrodes when anelectric circuit is closed throughv the spark plug.

It will be observedthat the electrodes project outwardly from the end ofthe casing a relatively great distance, so that the incoming freshcharge of gases in the engine Vcylinder will srveep the burned gasesaway trom the electrodes and carry any deposit of carbon therefrom, andalso the spark will be -formed at a point which will be well surroundedbythe fresh charge of gases. :The

result of'this arrangement is that the electrodes need cleaning muchless frequently than they would if they were short and perhaps partiallyhoused by the end et the casmg l.

' ,As will be ur. dcrstood, the connecting portion 5 between the twoarms of the electrode 5 stitlfens the arms so that the elec;-A

trode is not easily bent out ot' position in cleaning the plug whencleaning becomes necessary.

Ne claim as our invention:

In a spark plug of the character described, in combination, abushing-like casing adapt,- ed to be screwedinto an engine cylinder, aninsulating member in said casing, an elect-rode in the-form of a rodlying within said insulating member, means at one`v end of saidelectrode for attaching an electric wire thereto, the opposite end ofsaid electrede projecting a relatively great distance" beyond the end ofsaid casing, and 'a second electrode comprising a wire bentat its middleportion to torni two arms, the ends of which'are fixed in the end ofthecasing, the outer end of said arms adjacent tosaid bend being shaped tolie at opposite sides ot said l

